Which of these sentences lacks parallel structure?

Not only did Zach get a ticket for running a red light, but he also got a ticket for speeding.
I completed the assignment by rereading the chapter, took detailed notes, creating an outline, and then I studied all of it.
He doesn't know yet whether he will go to court to fight the ticket or if he will simply pay it.
If Zach ever gets to drive the car again, he promises he will both watch his speed and stop at red lights.

He doesn't know yet whether he will go to court to fight the ticket or if he will simply pay it.

Explanation:

in my opinion, ap calculus was the most difficult. i often struggled with it a lot. however, i have gotten a lot better.

impartial means: treating all rivals or disputants equally; fair and just.

i would say that impartial is agreeing with something, because impartial means to treat your rivals, arguments, and reasoning equally and fair. so if you rival says something, agreeing on it means you did the impartial.